1. Field of the Invention
The present invention relates to a nozzle cleaning apparatus, and more particularly, to an apparatus and method for cleaning a nozzle for automatically cleaning pollutant of the nozzle.
2. Discussion of the Related Art
Recently, a variety of flat panel displays, which are capable of solving heavy weight and bulky volume problems of cathode ray tubes, has been developed. Examples of the flat panel displays include a liquid crystal display (LCD) device, a field emission display (FED), a plasma display panel (PDP), and a light emitting display (LED).
Among the variety of flat panel displays, the LCD devices are designed to display images by regulating light transmissibility of liquid crystals using electric fields. These LCD devices include liquid crystal panels, in which liquid crystal cells are arranged in a matrix form, and drive circuits which drive the liquid crystal panels.
The liquid crystal panels are provided with common electrodes and pixel electrodes to apply an electric field to each of the liquid crystal cells. Conventionally, the pixel electrodes are formed on a lower substrate at positions of the respective liquid crystal cells. On the other hand, the common electrodes are integrally formed over a surface of an upper substrate. Each of the pixel electrodes is connected to a thin film transistor (hereinafter, referred to as “TFT”) that is used as a switch device. The pixel electrodes are used to drive the liquid crystal cells along with the common electrodes in accordance with data signals supplied through the TFTs.
Generally, a method for manufacturing the liquid crystal panel comprises a substrate cleaning process, a substrate patterning process, an alignment film forming process, and a substrate assembling/liquid crystal forming process.
In the substrate cleaning process, foreign substances on first and second substrates are removed by use of cleaning agents prior to and after patterning the first and second substrates.
The substrate patterning process is divided into a first substrate patterning and a second substrate patterning. The first substrate is formed with color filters, common electrodes, and black matrices, and the second substrate is formed with a variety of signal lines including data lines and gate lines. The TFTs are formed at positions where the data lines and the gate lines intersect. The pixel electrodes are formed at pixel regions between the data lines and the gate lines. In the substrate patterning process, a photolithography method using a photoresist is generally used for the patterning of each layer.
In the alignment film forming process, first, alignment films are applied to both the first and second substrates, and then, the applied alignment films are rubbed via a rubbing process.
The substrate assembling/liquid crystal forming process includes a process for assembling the first and second substrates using a seal, a process for injecting liquid crystals, and a process for sealing a liquid crystal injection hole, these processes being performed in this sequence. Alternatively, the substrate assembling/liquid crystal forming process may include a seal process for forming a seal on the first substrate or second substrate, a loading process for loading liquid crystals on the substrate formed with the seal, and a process for assembling the first and second substrates to each other, these processes being performed in this sequence. Here, the liquid crystals are formed in a liquid crystal space, which is defined between the first and second substrates by ball spacers or column spacers.
The photolithography method, which is used in the substrate patterning process included in the manufacture of the liquid crystal panel to pattern each layer including the TFTs and signal lines, includes a coating process for coating a photoresist on the substrate, an exposure process for selectively irradiating light on the photoresist by use of a photo mask, and a developing process for developing the exposed photoresist.
In the coating process, the photoresist is coated on the substrate in accordance with rotation of a rotary chuck.
As shown in FIG. 1, a conventional rotary type photoresist coating apparatus includes a rotary chuck 10 to be mounted in a rotary cup (not shown), a substrate 20 loaded on the rotary chuck 10, and a nozzle 30 to dispense a photoresist 32 onto the substrate 20 through an outlet thereof.
The rotary chuck 10 is adapted to rotate by a driving shaft 12, which cooperates with a drive device (not shown), while supporting the substrate 20 which is loaded thereon from an external station.
The substrate 20 has a layer to be patterned via the photolithography method.
The nozzle 30 is designed to receive the photoresist 32 supplied from an external photoresist source, so as to dispense the photoresist 32 onto the substrate 20 in the form of droplets.
In operation of the conventional rotary type photoresist coating apparatus, if the substrate 20 is loaded on the rotary chuck 10, the photoresist 32 is dispensed in the form of droplets on the substrate 20 through the nozzle 30. Then, the rotary chuck 10 is rotated along with the rotary cup, whereby the photoresist 32, dispensed on the substrate 20, is spread and coated over a surface of the substrate 20.
A problem of the conventional rotary type photoresist coating apparatus is that the greater the use frequency of the nozzle 30, the more likely some of the photoresist 32 may accumulate at the outlet and surface of the nozzle 30, resulting in nozzle pollution.
The conventional rotary type photoresist coating apparatus, however, has no cleaning device to clean pollutant of the nozzle 30, and therefore, requires a skilled person to frequently clean the pollutant of the nozzle 30 by use of a wiper with a thinner.
Accordingly, the conventional rotary type photoresist coating apparatus suffers from troublesome manual operation for cleaning the pollutant of the nozzle 30, and therefore, results in consumption of labor and increased cleaning time.